1. The Field of the Invention
The present invention relates to catheters and more particularly, the present invention is related to a dual-lumen catheter for use in extracorporeal oxygenation or other similar applications.
2. The Present State of the Art
In response to the need of patients with respiratory distress who fail to respond to conventional ventilatory management, many extracorporeal life support (ECLS) procedures and techniques have been developed to provide pulmonary and/or cardiac support for such patients. Extracorporeal membrane oxygenation (ECMO) is a life support technique which employs a cardiopulmonary bypass with a heart-lung machine to provide gas exchange, and to permit lungs to rest from damaging pressure and oxygen associated with conventional ventilation therapy. ECMO is often associated with neonatal respiratory dysfunction.
At the present time, two ECMO procedures are well known: venoarterial (VA) ECMO and venovenous (VV) ECMO. VA ECMO entails circulating the patient's blood through an extracorporeal system which pumps, oxygenates, and warms the blood. In order to withdraw the blood from the patient the right internal jugular vein is cannulated for venous drainage. The right common carotid artery is also cannulated for perfusion of the machine-oxygenated blood.
VV ECMO also entails circulating the patient's blood through an extracorporeal system which pumps, oxygenates and warms the blood. The distinction lies in the drainage and perfusion of blood. In VV ECMO, blood drainage is also accomplished by cannulation of the right jugular. However perfusion takes place in a vein rather than an artery. In VA ECMO, the perfusion of oxygenated blood is into the common carotid artery by employing a cannula placed in the common carotid artery at the level of the aortic arch. In VV ECMO, the perfusion of the oxygenated blood is into the femoral vein by employing a cannula secured in the femoral vein. This spares the common carotid artery.
In both VA and VV ECMO, the cannulation of the right jugular for drainage requires insertion of a catheter down the right jugular, into the superior vena cava, and into the right atrium of the heart. It is from the right atrium that blood drainage typically occurs in ECMO. Withdrawal of the blood from the right atrium is typically by gravity flow and the blood enters an extracorporeal circuit which oxygenates and warms the blood to suitable levels The extracorporeal circuit then pumps the oxygenated blood back into the patient for circulation in the body.
One drawback of both VA ECMO and VV ECMO is the necessary ligation of two primary veins and/or arteries. It is generally accepted that ligation poses the threat of future neurologic complications. Attempts to solve this problem have led to procedures involving a single ligation and cannulation, which use a tidal flow method (TF). In other words, the action of withdrawal and perfusion are mutually exclusive with respect to time through the same passage in a single cannula. While TF ECMO reduces the number of ligations from two to one it does not permit continuous and simultaneous withdrawal and perfusion of blood, and also results in recirculation of venous blood with oxygenated blood, since both withdrawal and return occur at the same site. Accordingly, it would be an important advance in the art to provide an apparatus and method which would permit the number of ligations necessary to provide ECLS to be reduced to one rather than two without being limited to a tidal flow method with its attendant disadvantages.